The University of Chicago Cancer Research Center Viral Oncology Research Program is a multidisciplinary research effort directed toward elucidation of the expression of the gene function of herpesviruses (herpes simplex virus 1 and 2 and Epstein-Barr virus) and oncornaviruses in human cells. The herpesvirus projects have as their major objective identification of viral gene products, and regulation of their expression in lytic infection and in transformed cells. The oncornavirus project is focused on C type virus gene expression, the factors controlling its expression in infected cells in culture and on the expression of this virus in human disease.